The present invention relates generally to instrumentation to be used in revision surgery, and more particularly, to instrumentation that allows trial reduction prior to femoral resection.
A natural joint in the human body such as a knee joint may undergo degenerative changes due to a variety of etiologies. When these degenerative changes become advanced and are irreversible, it may ultimately become necessary to replace the natural joint with a prosthetic joint. Such a prosthetic joint often includes several biocompatible components which are formed from high strength synthetic materials. These materials are not only able to accommodate the various loading conditions that the prosthetic joint may encounter, but are also biocompatible with the human body.
While such knee joint prostheses have been effective in replacing the anatomical knee joint, revision surgery is sometimes required to replace a knee joint prosthesis when such factors as bone deterioration occurs. In such revision surgery, the existing femoral component is removed from the distal femur and then the distal femur is prepared to accept the femoral component of a new knee joint prosthesis. In this regard, the tibia is first resected so as to leave a flat surface. The valgus angle of the femur is then determined and a distal resection is made based on the valgus angle. Further femoral resection is performed, the orientation of which is based on the distal resection. Trial reduction is then performed to obtain proper placement of the femoral component.
While revision surgery is generally successful in replacing the primary knee joint prosthesis with a revision knee joint prosthesis, such revision surgery is often relatively complicated. If the femoral component does not fit properly, adjustment cuts, augments or other alternative adjustments must be made. These adjustments are not easily performed and proper positioning of the prosthesis is often difficult to achieve. In addition to the foregoing, revision surgery is often complicated due to bone loss. Specifically, bony landmarks used in primary prosthesis surgery as cutting guides are unavailable due to distal and posterior femoral bone loss.
Accordingly, it is desired to provide a system which allows trial reduction prior to femoral resection, and wherein the trial reduction dictates where resection should be made to accommodate proper placement of the prosthesis.